A field emission display (FED) has a cathode with a matrix addressable array of thin film, cold field emitters and a phosphor-coated anode formed on a faceplate. The cathode may be formed as part of a backplate or it may be spaced from a separate backplate. The cathode emitters bombard the anode with electrons to provide a light image that can be viewed.
The backplate and faceplate are sealed in a package so that there is a very small space between the faceplate and the cathode. The package has a high vacuum to assure that the space between the anode and cathode is substantially devoid of material that could cause shorting. Contamination by residual gases, such as oxygen molecules, can adversely affect the performance of the display, and can even cause destruction.
In To prevent such destruction, a getter can be provided in the package to react with molecules generated during operation, thus preventing them from causing voltage breakdown within the device. While the getter thus addresses this problem, its placement within the FED is itself problematic. A getter can be placed to the side of the cathode, but such placement can increase the width of the display. The getter can be placed between the cathode and faceplate, but such placement may limit the resolution of the display.
After the getter is sealed in the package, it is activated. With a getter formed from an evaporable wire (as opposed to a non-evaporable powder), activation is typically performed by passing a current through the wire to heat it sufficiently to cause molecules to evaporate. To provide the current, the wire getter is coupled to electrical leads through the package seal to a power source. Passing electrical leads through the seal and heating of the leads while electrical current is being passed through, however, increases the likelihood that the seal's integrity will be compromised.